The objective of the project is to gain information with respect to the oral colonization of potentially-cariogenic or predominant plaque organisms and their relation to dental disease. The studies involve in vitro as well as in vivo approaches with rodents and humans. Topics of study are: 1) the role of sucrose in the colonization of S. mutans on the teeth, 2) factors influencing the colonization of Actinomyces viscosus on the teeth, 3) studies of the mechanism of the cariogenicity of plaque organisms, 4) the influence of tooth enamel "maturation" on the cariogenicity of acidogenic plaque organisms in rodents, 5) the role of acidogenic plaque bacteria, e.g. S. mutans, Actinomyces sp., lactobacilli in the initiation of dental caries; plaque flora of "nursing bottle" caries, 6) acquisition and transmission of S. mutans: comparison of salivary levels in parents and their children, and 7) influence of dietary carbohydrate per se on the oral colonization of Streptococcus and Actinomyces species.